The Michigan Supreme Court has overturned a prior ruling that barred passengers from challenging a search of a car.
In a unanimous decision, the court said normally a passenger does not have a legitimate expectation of privacy in someone else's car.
But it ruled that in this case the passenger did have a legitimate expectation of privacy for a backpack that was clearly his.
The court decided the warrantless search of the passenger's backpack was unreasonable and violated the Fourth amendment.
It said the facts showed a reasonable police officer would not have believed the driver had the authority to consent to a search of the passenger's backpack.
And the passenger did not give his consent.
The court said, "a person can get in a car without leaving his Fourth Amendment rights at the curb."